28-pound rainbow trout caught in northern Idaho would have been record-breaker

Larry Warren caught the monster fish on Jan. 8 on Clearwater River in northern Idaho.
(Idaho Fish and Game)

A 28-pound rainbow trout was caught in a northern Idaho river last week—which would have been the largest in state history-- but it had to be released due to state laws protecting the threatened species.

A steelhead trout is a rainbow trout longer than 20 inches. These fish with a clipped adipose fin-- which is located behind its dorsal fin-- may be kept in other waters in the state. This particular fish's adipose fin was intact so it was required to be set free. The fish was also protected because it was caught on a river that mandated throwing the species back. Steelheads, indeed, are considered to be "threatened," under the Endangered Species Act.

"That's probably why it grew so large," Liebenthal said.

Edmund DeMarche is a news editor for FoxNews.com. Follow him on Twitter @EDeMarche.